As soon as I was taught that O2 is para-magnetic, a magnetic separation technique with flowing air and multiple stages seemed like a fairly trivial process for separation. I was expecting the patent to be for the 1930's or 40's when all of this physical property was first understood. Seeing a patent issued in 2007 for something so trivial does not seem to be in the spirit of advancing technology. It seems more like someone trying to get money without doing any mental labor. This is something that takes 4 seconds of thought: O2 is para-magnetic, so if I blow air over a magnet, the stream closest to the magnet will be oxygen enriched.

Does anyone have prior art on this? Perhaps any use of magnetic separation of a gas?

Note that the patent cites other patents, like US4704139, a 1987 patent by Hitachi: "Magnetic separation of air into oxygen and nitrogen". So the basis for the patent doesn't appear to be this trick alone; the patent office wasn't fooled into ignoring prior work about magnetic separation. That Hitachi patent, in turn, cites patents as old as 1913 for separating mixtures of gases.
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KazJul 22 '14 at 18:41